Conventional scholarship on international taxation tends to address competition. It focuses on governments and does not integrate purposeful political strategy with the ideational dimension of policy change. In this article we examine co-operation, use a multi-actor perspective to explain the selection of modes of governance and bridge the gap between the strategic and ideational components of policy change. We show how a political strategy pursued by the Commission has led to the emergence of two functionally differentiated governance arenas, dealing with different definitions of tax problems and operating with modes of governance that suit the internal logic of individual arenas. We then examine the limitations of political strategy, by showing how a third governance arena dominated by the European Court of Justice has become increasingly important, with little control exercised by the Commission and the Member States.